Due to increases in vandalic tampering with the contents of packages, particularly containers for medicaments, foods and the like, the art has sought convenient and inexpensive ways of protecting such containers from such vandalic tampering.
To avoid such vandalic tampering, the art has proposed the use of container closures which are essentially mechanically sealed, but this approach in the art has been generally unsuccessful, since once the mechanical seal is broken, reclosing the container for subsequent intermittent use by the consumer is difficult, and in some cases, impossible.
Another approach in the art is that of providing a closure which is difficult to open, and not convenient for surreptitious opening while the container remains on the retail store shelf. However, these difficult to open closures are most inconvenient to the user and do not ensure that tampering has not occurred.
The third, and more generally accepted approach in the art is that of providing a closure which, while it will not prevent tampering, will show most clearly and obviously when tampering has occured. These types of closures are referred to as tamper-evident closures and it is to this type of closure that the present invention is directed.
Tamper-evident closures, generally, are of the type where the closure has incorporated therewith some element which must either be very noticeably disturbed or broken when the closure is removed from the container. That element is generally referred to a "seal", not in that the closure is literally sealed in the sense of containment, but in the sense of a legal seal, where the disturbance or destruction thereof indicates tampering. Copending and commonly assigned U.S. Patent Application Ser. No. 424,431, filed on Sept. 27, 1982 is an example of a "sealed" closure.
Sealed closures have one very distinct disadvantage and problem. The seal which is either disturbed or broken in removing the closure, must be such an obvious seal that the ordinary consumer can easily detect that something is amiss. For example, if the seal is nothing more than a heat-shrunk film about the closure, the removal thereof in tampering with the container may not result in an obvious disturbance of the container closure. Since consumers are accustomed to many packages not being so sealed, the absence of the seal may not be detected by many consumers.
As another example of a sealed container, metal or plastic film may be glued across the finish of the container, but those films can be removed by the vandal, and again it may not be obvious to the ordinary consumer that the film seal has been removed. Other examples of the difficulties faced by the art in providing sealed containers may be given, but basically the overall problem is that of providing a closure where the absence of the seal will be most obvious to the ordinary consumer. This problem has not been adequately solved for many containers, since ordinary consumers do not now know which containers ordinarily have a seal and which do not, and the absence of the seal may not be conspicuous to the oridinary consumer.
It would therefore be a substantial advantage in the art to provide a tamper-evident closure wherein evidence of the first removal of the closure from the container is permanently displayed on the closure and warns the consumer that that closure has been previously removed from the container. Such a closure would provide even the least discerning consumer with the information that that closure had been previously removed, whether or not the consumer would ordinarily expect that container to be sealed.